Add adapter session codecs with cwd-aware resume and unknown-session retry

Introduce AdapterSessionCodec interface for structured session serialization,
deserialization, and display ID extraction. Implement codecs for claude_local
and codex_local adapters with cwd validation — sessions saved for a different
working directory are not resumed. Both adapters now return sessionParams and
sessionDisplayId alongside legacy sessionId.

Add isCodexUnknownSessionError detection and automatic retry with fresh session
for codex_local (matching existing claude_local behavior). Inject approval
context env vars (PAPERCLIP_APPROVAL_ID, PAPERCLIP_APPROVAL_STATUS,
PAPERCLIP_LINKED_ISSUE_IDS) into adapter environments.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/adapters/codex-local/src/server/parse.ts

@@ -45,3 +45,14 @@ export function parseCodexJsonl(stdout: string) {
     usage,
   };
 }
+
+export function isCodexUnknownSessionError(stdout: string, stderr: string): boolean {
+  const haystack = `${stdout}\n${stderr}`
+    .split(/\r?\n/)
+    .map((line) => line.trim())
+    .filter(Boolean)
+    .join("\n");
+  return /unknown (session|thread)|session .* not found|thread .* not found|conversation .* not found/i.test(
+    haystack,
+  );
+}